title: Creatine and guanidinoacetate reference values in a French population.
abstract: Creatine and guanidinoacetate are biomarkers of creatine metabolism. Their assays in body fluids may be used for detecting patients with primary creatine deficiency disorders (PCDD), a class of inherited diseases. Their laboratory values in blood and urine may vary with age, requiring that reference normal values are given within the age range. Despite the long known role of creatine for muscle physiology, muscle signs are not necessarily the major complaint expressed by PCDD patients. These disorders drastically affect brain function inducing, in patients, intellectual disability, autistic behavior and other neurological signs (delays in speech and language, epilepsy, ataxia, dystonia and choreoathetosis), being a common feature the drop in brain creatine content. For this reason, screening of PCDD patients has been repeatedly carried out in populations with neurological signs. This report is aimed at providing reference laboratory values and related age ranges found for a large scale population of patients with neurological signs (more than 6 thousand patients) previously serving as a background population for screening French patients with PCDD. These reference laboratory values and age ranges compare rather favorably with literature values for healthy populations. Some differences are also observed, and female participants are discriminated from male participants as regards to urine but not blood values including creatine on creatinine ratio and guanidinoacetate on creatinine ratio values. Such gender differences were previously observed in healthy populations; they might be explained by literature differential effects of testosterone and estrogen in adolescents and adults, and by estrogen effects in prepubertal age on SLC6A8 function. Finally, though they were acquired on a population with neurological signs, the present data might reasonably serve as reference laboratory values in any future medical study exploring abnormalities of creatine metabolism and transport.
authors.affiliation: Département de Biochimie et Biologie Moléculaire, Laboratoire d'Hormonologie, Metabolisme-Nutrition & Oncologie (HMNO) - Centre de Biologie et Pathologie (CBP) Pierre-Marie Degand, CHRU Lille, 59037 Lille, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Joncquel-Chevalier Curt
authors.forename: David
authors.initials: D
authors.lastname: Cheillan
authors.forename: Gilbert
authors.initials: G
authors.lastname: Briand
authors.forename: Gajja S
authors.initials: GS
authors.lastname: Salomons
authors.forename: Karine
authors.initials: K
authors.lastname: Mention-Mulliez
authors.forename: Dries
authors.initials: D
authors.lastname: Dobbelaere
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Cuisset
authors.forename: Laurence
authors.initials: L
authors.lastname: Lion-François
authors.forename: Vincent
authors.initials: V
authors.lastname: Des Portes
authors.forename: Allel
authors.initials: A
authors.lastname: Chabli
authors.forename: Vassili
authors.initials: V
authors.lastname: Valayannopoulos
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Benoist
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Pinard
authors.forename: Gilles
authors.initials: G
authors.lastname: Simard
authors.forename: Olivier
authors.initials: O
authors.lastname: Douay
authors.forename: Kumaran
authors.initials: K
authors.lastname: Deiva
authors.forename: Marc
authors.initials: M
authors.lastname: Tardieu
authors.forename: Alexandra
authors.initials: A
authors.lastname: Afenjar
authors.forename: Delphine
authors.initials: D
authors.lastname: Héron
authors.forename: François
authors.initials: F
authors.lastname: Rivier
authors.forename: Brigitte
authors.initials: B
authors.lastname: Chabrol
authors.forename: Fabienne
authors.initials: F
authors.lastname: Prieur
authors.forename: François
authors.initials: F
authors.lastname: Cartault
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Pitelet
authors.forename: Alice
authors.initials: A
authors.lastname: Goldenberg
authors.forename: Soumeya
authors.initials: S
authors.lastname: Bekri
authors.forename: Marion
authors.initials: M
authors.lastname: Gerard
authors.forename: Richard
authors.initials: R
authors.lastname: Delorme
authors.forename: Nicole
authors.initials: N
authors.lastname: Porchet
authors.forename: Christine
authors.initials: C
authors.lastname: Vianey-Saban
authors.forename: Joseph
authors.initials: J
authors.lastname: Vamecq
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003401:Creatine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D005260:Female; D005602:France; D005998:Glycine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000652:urine; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012737:Sex Factors; D044465:White People; D055815:Young Adult
chemical_list: C004946:glycocyamine; D003401:Creatine; D005998:Glycine
keywords: Creatine; Creatinine; Guanidinoacetate; Laboratory values; Plasma; Urine